Disposable syringes are in widespread use for a number of different types of applications. For example, syringes are used not only to withdraw a fluid (e.g., blood) from a patient but also to administer a medication to a patient. In the latter, a cap or the like is removed from the syringe and a unit dose of the medication is carefully measured and then injected or otherwise disposed within the syringe.
As technology advances, more and more sophisticated, automated systems are being developed for preparing and delivering medications by integrating a number of different stations, with one or more specific tasks being performed at each station. For example, one type of exemplary automated system operates as a syringe filling apparatus that receives user inputted information, such as the type of medication, the volume of the medication and any mixing instructions, etc. The system then uses this inputted information to disperse the correct medication into the syringe up to the inputted volume.
In some instances, the medication that is to be delivered to the patient includes more than one pharmaceutical substance. For example, the medication can be a mixture of several components, such as several pharmaceutical substances.
By automating the medication preparation process, increased production and efficiency are achieved. This results in reduced production costs and also permits the system to operate over any time period of a given day with only limited operator intervention for manual inspection to ensure proper operation is being achieved. In addition, reduced human intervention provides reduced opportunities for bacteriological contamination. Such a system finds particular utility in settings, such as large hospitals, where a large number of doses of medications that must be prepared daily. Traditionally, these doses have been prepared manually in what is an exacting but tedious responsibility for a highly skilled staff. In order to be valuable, automated systems must maintain the exacting standards set by medical regulatory organizations, while at the same time simplifying the overall process and reducing the time necessary for preparing the medications.
Because syringes are used often as the carrier means for transporting and delivering the medication to the patient, it is advantageous for these automated systems to be tailored to accept syringes. However, the previous methods of dispersing the medication from the vial and into the syringe were very time consuming and labor intensive. More specifically, medications and the like are typically stored in a vial that is sealed with a safety cap or the like. In conventional medication preparation, a trained person retrieves the correct vial from a storage cabinet or the like, confirms the contents and then removes the safety cap manually. This is typically done by simply popping the safety cap off with one's hands. Once the safety cap is removed, the trained person inspects the integrity of the membrane and cleans the membrane. An instrument, e.g., a needle, is then used to pierce the membrane and withdraw the medication contained in the vial. The withdrawn medication is then placed into a syringe to permit subsequent administration of the medication from the syringe.
If the medication needs to be reconstituted, the medication initially comes in a solid form and is contained in an injectable drug vial and then the proper amount of diluent is added and the vial is agitated to ensure that all of the solid goes into solution, thereby providing a medication having the desired concentration. The drug vial is typically stored in a drug cabinet or the like and is then delivered to other stations where it is processed to receive the diluent.
A special case exists when doses need to be prepared in quantities smaller than are ordinarily used either because the patient is a child or because the patient has other underlying conditions that make them intolerant of ordinary doses of a particular drug. In such cases the dose may be so small as to be immeasurable with sufficient accuracy at commercially available concentrations. In such cases, pharmacies prepare dilutions of the commercially available injections so that the required dose is delivered in a larger, more measurable fluid volume. This process is even more time-consuming and exacting than the previously described dose preparation in that the pharmacist must first prepare the commercially available product, then remove an aliquot from that product, inject it into a sterile empty vial, compute an additional diluent amount, measure and inject that diluent into the sterile empty vial (to produce the dilution), and then label the vial to ensure that its contents are clearly and accurately known. Each of these additional steps adds time, opportunity for manual measurement error and opportunity for microbial contamination.
This limitation also exists for automated systems in that they may have limits to the fluid volume of doses they can prepare accurately, or the dose container (such as syringe) into which they place the dose cannot accurately deliver doses below a specified volume.
What is needed in the art and has heretofore not been available is a system and method for automating the medication preparation process and more specifically, an automated system and method for preparing a syringe including the filling of medication therein and also an automated serial dilution technique, as well as a number of safety features that improve the integrity of the process.